Fig. 6.

Proposed role of PID in phospholipid-mediated membrane targeting. PDK1 is localized to specific membrane regions by binding through the pleckstrin homology (PH) domain to locally produced phosphoinositide ligands. PID is recruited to the membrane through the interaction of PDK1 with the PID PIF domain. PDK1 phosphorylation of Ser 290 within the activation loop stimulates PID autophosphorylation. Active PID phosphorylates substrate proteins, resulting in the targeted localization of the polar auxin transport complex machinery.